Fix consistently failing CentOS gate

This fixes a gate regression and probably regression in general
with building images.  I'm not sure where the regression came from,
but I suspect a new verson of MySQL-python from pip is to blame.

Closes-Bug: #1561347
Change-Id: Ib502d0090a3fc3b3ea5d27a91ff59df1f53c01a3

docker/kolla-toolbox/Dockerfile.j2

@@ -10,6 +10,7 @@ RUN yum -y install \
         libxml2-devel \
         libxslt-devel \
         MariaDB-devel \
+        MySQL-python \
         openssl-devel \
         python-devel \
         openssh-clients \
@@ -26,6 +27,7 @@ RUN apt-get -y --no-install-recommends install \
         libmariadbclient-dev \
         libssl-dev \
         libxslt1-dev \
+        python-mysqldb \
         python-dev \
     && apt-get clean
 
@@ -35,7 +37,6 @@ RUN curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py \
     && python get-pip.py \
     && rm get-pip.py \
     && pip --no-cache-dir install \
-        MySQL-python \
         os-client-config==1.16.0 \
         pyudev \
         shade==1.4.0